We do not (and to a large extent, cannot) know who we are through introspection.

Conscious awareness is a sliver of the machine that is human intelligence but it's the only aspect we experience and hence the only aspect we come to believe exists. Thoughts, feelings, and behavior operate largely without deliberation or conscious recognition — it's the routinized, automatic, classically conditioned, pre-compiled aspects of our thoughts and feelings that make up a large part of who we are. We don't know what motivates us even though we are certain we know just why we do the things we do. We have no idea that our perceptions and judgments are incorrect (as measured objectively) even when they are. Even more stunning, our behavior is often discrepant from our own conscious intentions and goals, not just objective standards or somebody else's standards.

The same lack of introspective access that keeps us from seeing the truth in a visual illusion is the lack of introspective access that keeps us from seeing the truth of our own minds and behavior. The "bounds" on our ethical sense rarely come to light because the input into those decisions is kept firmly outside our awareness. Or at least, they don't come to light until science brings them into the light in a way that no longer permits them to remain in the dark.

It is the fact that human minds have a tendency to categorize and learn in particular ways, that the sorts of feelings for one's ingroup and fear of outgroups are part of our evolutionary history. That fearing things that are different from oneself, holding what's not part of the dominant culture (not American, not male, not White, not college-educated) to be "less good" whether one wants to or not, reflects a part of our history that made sense in a particular time and place - because without it we would not have survived. To know this is to understand the barriers to change honestly and with adequate preparation.

As everybody's favorite biologist Richard Dawkins said thirty years ago:

Let us understand what our own selfish genes are up to, because we may then at least have a chance to upset their designs, something that no other species has ever aspired to do.

We cannot know ourselves without the methods of science. The mind sciences have made it possible to look into the universe between the ear drums in ways that were unimagined.

Emily Dickinson wrote in a letter to a mentor asking him to tell her how good a poet she was: "The sailor cannot see the north, but knows the needle can" she said. We have the needle and it involves direct, concerted effort, using science to get to the next and perhaps last frontier, of understanding not just our place among other planets, our place among other species, but our very nature.